Using resource controller and namespace

app/controllers/spree/digitals_controller.rb

@@ -0,0 +1,18 @@
+module Spree
+  class DigitalsController < Spree::BaseController
+  
+    ssl_required :show
+  
+    def show
+      link = DigitalLink.find_by_secret(params[:secret])
+      if link.present? and link.digital.attachment.present?
+        attachment = link.digital.attachment
+        if link.authorize! and File.file?(attachment.path)
+          send_file attachment.path :filename => attachment.original_filename, :type => attachment.content_type and return
+        end
+      end
+      render :unauthorized
+    end
+    
+  end
+end